JPH0471943B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel and useful resin dispersion and a method for making the resin dispersion. In more detail,
The present invention provides a specific polyalkylene glycol,
Certain α,β-ethylenically unsaturated monomers (hereinafter referred to as
Also called polymerizable vinyl monomer. ), a cationic or amphoteric type copolymer (hereinafter also referred to as vinyl copolymer) that does not contain so-called emulsifiers and protective colloids, and a polyalkylene glycol and a water-soluble organic solvent. The present invention relates to an aqueous resin dispersion comprising: and a method for producing the aqueous resin dispersion. Water-based coating agents have attracted particular attention in recent years because they are low-pollution and resource-saving, and there are two types of base resins: water-soluble and water-dispersible, each with their own unique characteristics. However, in general, the drying properties, water resistance, gloss, or adhesion of the coating film to the substrate remain issues that must be solved. Among these, water-soluble type resins include so-called anion type resins, in which carboxyl groups present in the resin are neutralized and dissolved with alkali such as ammonia or amines, and tertiary type resins present in the resin. So-called cationic resins, in which amino groups are neutralized and dissolved with acid, are already commercially available, and although both of these types of resins have good gloss and adhesion, they usually require an organic solvent amount of 30 to 50%. Since it is contained in a large amount by weight, there are problems in terms of anti-pollution measures, and there are also disadvantages in that the drying properties and water resistance of the coating film are poor. On the other hand, dispersions obtained by emulsion polymerization in the presence of emulsifiers and protective colloids or dispersions obtained by mechanical dispersion can contain high molecular weight polymer molecules regardless of the viscosity of these dispersions. However, even if it has a high solid content concentration, it can be made to have a low viscosity, and it has excellent drying properties because it does not use organic solvents or amines that affect safety and odor. However, it has drawbacks such as poor coating gloss and workability, and poor coating film water resistance and poor adhesion to substrates due to the effects of the emulsifiers and protective colloids used. Therefore, colloidal dispersion resins that take advantage of the advantages of both water-soluble resins and water-dispersible resins are currently being studied. Against this background, the present inventors conducted intensive studies to solve the various pending problems, and as a result, introduced a polymerizable vinyl monomer having a tertiary amino group as an essential monomer into the polymerization reaction system. Furthermore, an aqueous resin dispersion obtained by adding water to a vinyl copolymer solution obtained by using a water-soluble solvent solution containing a specific amount of polyalkylene glycol as a medium can be used as an emulsifier and a protective colloid. The present inventors have now completed the present invention by discovering that the present invention is stable on its own without causing any problems, and provides a coating film with high adhesion and excellent water resistance. That is, the present invention comprises, in part, 2 to 35 parts by weight of an α,β-ethylenically unsaturated monomer having a tertiary amino group, and another α,β-ethylenically unsaturated monomer copolymerizable therewith. 98 to 65 parts by weight of β-ethylenically unsaturated monomer were dissolved in polyalkylene glycol (hereinafter abbreviated as polyalkylene glycol) having a molecular weight of 600 to 20,000 and essentially including polyethylene glycol. Water-soluble organic solvent (hereinafter referred to as
Abbreviated as water-soluble solvent. ), an aqueous resin dispersion (hereinafter also referred to as a dispersion or resin dispersion) comprising a copolymer obtained by polymerization, a water-soluble solvent, and the above-mentioned polyalkylene glycol. Second, in a solution of a water-soluble solvent in which a polyalkylene glycol having a molecular weight of 600 to 20,000 is dissolved, α,β-
2 to 35 parts by weight of an ethylenically unsaturated monomer and 98 to 65 parts by weight of another α,β-ethylenically unsaturated monomer that can be copolymerized therewith are polymerized, and then,
We also provide a method for producing an aqueous resin dispersion comprising the above copolymer, the above water-soluble solvent, and the above polyalkylene glycol, which comprises dispersing the thus obtained copolymer with water. That is. Here, in the present invention, the above-mentioned tertiary amino group-containing polymerizable vinyl monomer is used as an essential component compound because the copolymer obtained using the monomer has a water-dispersible property when acid neutralized. The aim is to achieve both the effect of imparting properties and the effect of exhibiting excellent adhesion to various substrates.
On the other hand, polymerization in a system containing the polyalkylene glycol involves simultaneous chemical bonding (grafting, etc.) and physical fusion between the vinyl copolymer and the polyalkylene glycol, resulting in the formation of the vinyl copolymer. The aim is to coalesce into a polymer with self-dispersion ability, thereby promoting the dispersion effect. Typical examples of the tertiary amino group-containing polymerizable vinyl monomer used in the present invention include dialkylaminoalkyl (meth)acrylates such as dimethylaminoethyl (meth)acrylate and diethylaminoethyl (meth)acrylate. , vinylpyridine such as vinylpyridine, 2-methyl-5-vinylpyridine;
Examples include dialkylaminoalkyl vinyl ethers such as dimethylaminoyl vinyl ether; alkylamino group-containing (meth)acrylamides such as dimethylaminoethyl (meth)acrylamide; these may be used alone or in combination of two or more. Typical examples of other polymerizable vinyl monomers that can be copolymerized with these tertiary amino group-containing polymerizable vinyl monomers include vinyl esters such as vinyl acetate, vinyl propionate, and versatile acid; (meth) Alkyl esters of (meth)acrylic acid such as methyl acrylate, ethyl (meth)acrylate, and butyl (meth)acrylate; aromatic vinyl compounds such as styrene and vinyltoluene; α-olefins such as ethylene; dienes such as; vinyl halides such as vinyl chloride and vinylidene chloride; vinyl ethers such as methyl vinyl ether; dialkyl esters of unsaturated dibasic acids such as dialkyl maleate, dialkyl fumarate, and dialkyl itaconate. These may be used alone or in combination of two or more. Furthermore, if necessary, unsaturated acids such as α, β-unsaturated ethylenic carboxylic acids, vinyl sulfonic acid, styrene sulfonic acid, or salts thereof;
(Meth)acrylamide or N-methylolated products thereof or alkoxylated products of the methylolated products; hydroxyl group-containing α,β-ethylenically unsaturated monomers such as β-hydroxyethyl methacrylate; glycidyl (meth)acrylate, allyl glycidyl ether A small amount of glycidyl group-containing α,β-ethylenically unsaturated monomers such as
This shows distinctive performance. In the composition of the vinyl copolymer, the above-mentioned tertiary amino group-containing polymerizable vinyl monomer is added to
The reason why the content is 35 parts by weight is that if it is less than 2 parts by weight, the water dispersibility will be insufficient, and the cationic properties will be reduced, making it impossible to fully exhibit properties such as adhesion. If it exceeds this range, the hydrophilicity will increase and the water resistance will decrease, and furthermore, due to the high water solubility, it will be difficult to obtain the desired dispersion, so it is limited. More preferably, the amount is within the range of 5 to 15 parts by weight based on 100 parts by weight of the total vinyl monomer. On the other hand, regarding the amount of polyalkylene glycol used in combination, the balance between the dispersibility imparting effect of the vinyl copolymer and the desired performance such as water resistance of the coating film, and the desired degree of neutralization of the resin dispersion are determined. Although it should be determined from the design plan, if the amount of the polyalkylene glycol used is 10 parts by weight or more based on 100 parts by weight of the total polymerizable vinyl monomer, the aqueous content of the vinyl copolymer can be improved without neutralization. It has the advantage of being decentralized. However, even if the amount used exceeds 20 parts by weight, the grafting efficiency will hardly be improved, and moreover, the water resistance will deteriorate.
On the other hand, if the amount used is less than 1 part by weight, it becomes difficult to obtain a dispersing effect. Regarding the molecular weight of the polyalkylene glycol, if it is less than 600, it will have poor hydrophilicity and a dispersing effect cannot be expected, whereas if it has a molecular weight exceeding 20,000, it will not be possible to graft it with the vinyl copolymer or dispersion effect. Fusion with copolymers is also less likely to occur,
The dispersion effect does not improve. Typical examples of the polyalkylene glycol include polyethylene glycol, polypropylene glycol, or a block combination of these polyethylene glycols and polypropylene glycol.
Examples include copolymers, and these may be used alone or in combination of two or more. In order to prepare a resin dispersion liquid by dispersing the vinyl copolymer obtained using the raw materials listed above in water, there are two methods: a method of dispersing using only water, and a method of dispersing using water and acids. There is a method of dispersing the dispersion liquid, but it is preferable to use the former method when preparing an amphoteric dispersion, and the latter method when preparing a cationic dispersion. Typical acids used to neutralize the resin dispersion include organic acids such as formic acid and acetic acid, and inorganic acids such as hydrochloric acid. Select a material that has the ability to dissolve the vinyl copolymer, does not cause problems such as wrinkles or sag when it is made into a paint, and has excellent drying properties and is suitable for application. Desirably, water-soluble ones such as alcohol-based, cellosolve-based, carbitol-based and derivatives thereof are applicable, and any known and commonly used ones can be used as they are. The amount of the water-soluble solvent used is 20 to 20 parts by weight per 100 parts by weight of the resin solid content of the resin dispersion.
A range of 100 parts by weight is desirable. If it is less than 20 parts by weight, the solution viscosity will increase during the reaction, which will hinder the progress of the polymerization reaction, and if it exceeds 100 parts by weight, the viscosity of the resin dispersion will increase and the dispersion stability will decrease. This would also go against the purpose of resource conservation. More preferably, it should be designed to be kept at 30% by weight or less in the final resin dispersion. Further, the amount of the solvent can be further reduced by adding water or the like to the vinyl copolymer solution for dispersion and then distilling a low boiling point water-soluble solvent under reduced pressure. The above-mentioned polymerization reaction may be carried out according to a conventional solution polymerization reaction method, and is not particularly limited. Next, the vinyl copolymer resin solution can be dispersed in water by adding the resin solution into water and dispersing it, or conversely by injecting water into the resin solution and dispersing it. Regardless of which method is used, it is desirable to heat the system to 50 to 100°C and slowly add the mixture under stirring to achieve dispersion. On the other hand, the acids used to neutralize the aqueous resin dispersion can be mixed either on the side where they are added or injected, or conversely on the side where they are added or injected. In order to obtain a stable dispersion, a method is adopted in which a fixed amount of acids is first mixed into a resin solution, and then water is added and injected into the neutralized resin solution to disperse it. is desirable. The thus obtained dispersion of the present invention can be used as it is as a coating agent, but if necessary, pigments, plasticizers or other solvents may be added to the dispersion of the present invention, or other miscible substances may be added to the dispersion of the present invention. It can also be used as a blend with water-based resins. The resin dispersion of the present invention can be obtained as a cationic or amphoteric type, but the cationic type has excellent adhesion to the anionic component in the substrate to be coated, and moreover, it can be used in combination systems. case,
In other words, it has good adhesion to the anionic groups in the binder components contained in the undercoat and topcoat paints, or to the anionic fillers or pigments in other additive components, so it has good adhesion as a finishing agent. It also has the advantage of improving performance. On the other hand, amphoteric types can also be used in a wide pH range, and there is very little selectivity of substrates with respect to such adhesion. Furthermore, the dispersion of the present invention can be directly kneaded with pigments, and has the advantage of having almost no problems with dispersion stability or foaming, unlike emulsion polymers using emulsifiers. The dispersion of the present invention or the coating composition obtained from the dispersion can be applied by dipping, brushing, spraying, roll coating, etc., and can be applied to wood, paper, fibers, etc. It can be applied to surfaces such as plastics, ceramics, leather, inorganic cement base materials, iron, and non-ferrous metals. Further, the use of the dispersion liquid of the present invention is not limited to painting, but can be used for a wide variety of purposes such as impregnation and adhesion. Next, the present invention will be specifically explained with reference to Examples and Comparative Examples, where all parts and percentages are based on weight unless otherwise specified. Example 1 In two flasks equipped with a stirrer, thermometer, reflux condenser, dropping funnel and inert gas inlet,
300 parts of butyl cellosolve and 70 parts of "polyethylene glycol #6000" [polyethylene glycol manufactured by Daiichi Kogyo Seiyaku Co., Ltd.; average molecular weight = 2700-3400]
The temperature was raised to 120°C while blowing nitrogen gas. Separately, 455 parts of methyl methacrylate, 210 parts of n-butyl acrylate, and 35 parts of dimethylaminoethyl acrylate were weighed and mixed in advance, and on the other hand, 14 parts of t-butyl hydroperoxide was weighed in advance and the mixture was added from a separate drip port. It took 3 hours for each drop to polymerize in a dropwise manner.
The polymerization was further maintained at the same temperature for 2 hours to complete the polymerization. Thereafter, the mixture was cooled to 80°C, and a solvent prepared by dissolving 6 parts of 88% formic acid in 870 parts of water was added dropwise over 2 hours to achieve dispersion, and then the temperature was lowered to 25°C. The target resin dispersion obtained in this way has a non-volatile content (NV) of 40%, a viscosity (Bruck-Field viscosity at 25°C; hereinafter the same) of 2500 cps,
And the pH was 5.6. Example 2 In a flask similar to Example 1, 300 parts of ethyl carbitol and 100 parts of "polyethylene glycol #6000" were charged and heated to 100°C in a nitrogen stream, while 421 parts of methyl methacrylate,
224 parts of 2-ethylhexyl methacrylate and 35 parts of dimethylaminoethyl methacrylate were weighed and mixed in advance, along with 7 parts of t-butylperoxy-2-ethylhexanoate, and these were added from separate dropping ports. After the mixture was injected and polymerized dropwise for 3 hours, the same temperature was further maintained for 2 hours to complete the polymerization. After that, it was cooled to 90℃ and 907 parts of water was added dropwise over 2 hours to achieve dispersion.
The mixture was cooled to ℃ and allowed to cool down. The target resin dispersion obtained here has an NV of 40%,
The viscosity was 2500 cps and the pH was 6.1. Example 3 In a flask similar to Example 1, 150 parts of isopropyl alcohol and 150 parts of isopropylene glycol were added.
150 parts and "Polyethylene Glycol #4000"
150 parts of [product of the same company; average molecular weight = 7,400 to 9,000] was charged, and the temperature was raised to 80°C in a nitrogen stream. Separately, 266 parts of styrene, methyl methacrylate
70 parts of t-butylperoxy-2-
Seven parts of ethylhexanoate were weighed out, and these were injected from separate dropping ports to uniformly drop-polymerize over 3 hours, and the polymerization was further maintained at the same temperature for 2 hours to complete the polymerization. . Then, at the same temperature, 7 parts of 88% formic acid was added.
A solution prepared by dissolving 807 parts of water was added dropwise over 2 hours to disperse the solution, and then the temperature was lowered to 25°C. The resin dispersion obtained here has an NV of 40% and a viscosity of
It was 2700cps and PH was 5.6. Comparative Example 1 Same as Example 1 except that the same amount of "polyethylene glycol #6000" was added and dissolved after the polymerization of the polymerizable vinyl monomer was completed, and then dispersed with water. When similar operations were repeated, the viscosity of the system increased significantly and a stable dispersion could not be obtained. Comparative Example 2 A control was carried out in the same manner as in Example 1, except that the same amount of methacrylic acid was used instead of dimethylaminoethyl acrylate, and 876 parts of water was used instead of the formic acid aqueous solution. A resin dispersion liquid was obtained. This one has a NV of 40%, a viscosity of 310 cps, and a PH of 5.4
It was something like that. Comparative Example 3 The polymerization temperature was 80°C, and the monomer dropping time was 3
By the usual emulsion polymerization method using an emulsifier, with a holding time of 3 hours after the completion of dropping,
An emulsion polymer was obtained using the following raw materials. Methyl methacrylate 65 parts n-butyl acrylate 30〃 Methacrylic acid 5〃 Sodium dodecylbenzenesulfonate 4〃 Ammonium persulfate 0.3〃Water 156.4〃Total 260.7〃 The emulsion obtained here has an NV of 40%, a viscosity of 200 cps, and a PH of 3.5. It was hot. Comparative Example 4 Comparative Example 3 except that the raw materials were changed as shown below.
Emulsion and
A polymer was obtained. Methyl methacrylate 50 parts n-butyl acrylate 40〃 Methacrylic acid 10〃 Butyl cellosolve 70〃 t-Butyl peroxybenzoate 1〃 Triethylamine 12〃Water 70〃Total 253〃 The emulsion obtained here has an NV of 40%, a viscosity of 20000 cps, The pH was 9.2. Using the aqueous resin dispersions obtained in Examples 1 to 3 and the aqueous resins obtained in Comparative Examples 2 to 4, paints were prepared as shown below, and coatings were tested according to various tests as described below. The various coating films were then subjected to performance tests. Titanium oxide/silica/calcium carbonate = 50/
40/10 (weight ratio) PWC = 55% NV = 55% The results of the performance tests are summarized in Table 1, and the judgment criteria for each test are as follows. ○...Good △...Slightly poor ×...Poor The aqueous resin dispersion obtained in Example 2 was
The feature is that when the pH is set to the acidic side, the amino groups contained in the resin are neutralized and act as cations, whereas when set to the alkaline side, the carboxyl groups in the resin are neutralized and act as anions. This aqueous resin dispersion has good system stability in the pH range of 3 to 9, and can exhibit excellent adhesion effects on both anionic and cationic substrates. Incidentally, regarding how this dispersion liquid exhibits changes in viscosity within the above-mentioned PH range, the relationship between PH and viscosity is illustrated in FIG. 1. 【table】

[Brief explanation of the drawing]

Figure 1 shows the relationship between PH and viscosity for the amphoteric type aqueous resin dispersion obtained in Example 2 of the present invention, where the horizontal axis represents PH and the vertical axis represents viscosity (cps). shall represent.

Claims (1)

[Scope of Claims] 1. 2 to 35 parts by weight of an α,β-ethylenically unsaturated monomer having a tertiary amino group and other α,β-ethylenically unsaturated monomers that can be copolymerized therewith. 98 of monomer
- 65 parts by weight in a solution of a water-soluble organic solvent in which a polyalkylene glycol having a molecular weight of 600 to 20,000 and essentially including polyethylene glycol is dissolved, and
An aqueous resin dispersion comprising the above water-soluble organic solvent and the above polyalkylene glycol. 2. First, in a solution of a water-soluble organic solvent in which polyalkylene glycol, which has a molecular weight of 600 to 20,000 and essentially includes polyethylene glycol, is dissolved, an α,β-ethylenically unsaturated monomer having a tertiary amino group is dissolved. and 98 parts by weight of other α,β-ethylenically unsaturated monomers that can be copolymerized therewith.
-65 parts by weight, and then the copolymer thus obtained is dispersed with water, and is composed of the above-mentioned copolymer, the above-mentioned water-soluble organic solvent, and the above-mentioned polyalkylene glycol. A method for producing an aqueous resin dispersion.